Lumia 800 Screen burn

I have had my Lumia 800 for nearly 7 months now and noticed this a few days ago and seems to be a bit more prominent now so have got it swapped out by Orange.

When I have a white background the phone is showing signs of screen burn. See the image attached to this post bare in mind this was taken on another phone camera so not the best quality, but you can make out XBOX Live on the image.

I also found out speaking to Orange support that after 6 months support switches back to Nokia.

Has anyone else noticed thi